1. Field of the Invention
The present invention relates to an endoscope in which two or more kinds of adapters are individually attachable to and detachable from a distal end portion located at a distal end in an insertion direction of an insertion portion.
2. Description of the Related Art
As is well known, endoscopes are widely used in an industrial field, for example. The endoscopes used in the industrial field are capable of performing observation of flaws, corrosion and the like in objects, and various kinds of treatment and the like by elongated insertion portions being inserted into an inside of a jet engine, insides of piping of factories or the like that are insides of objects.
A configuration is well known, in which an objective lens unit, and an image pickup unit including an image pickup device such as a CCD are provided, and an illumination unit that illuminates an inside of an object and the like are provided, in a distal end portion located at a distal end side in the insertion direction of the insertion portion of an endoscope.
Further, a configuration is also well known, in which an objective lens unit and an illumination unit are provided in a known optical adapter (hereinafter, simply called an adapter) which is attachable to and detachable from the distal end portion of an insertion portion.
Further, as an adapter, a front-view adapter for observing a front side in the insertion direction of the insertion portion, and a side-view adapter for observing a lateral side different from the insertion direction are well known, and the respective adapters are properly used in accordance with objects to be observed and use purposes.
Furthermore, in the respective front-view adapters and side-view adapters, a plurality of adapters with different viewing angles are present, and the adapters are also properly used in accordance with objects to be observed and use purposes. Further, in the respective front-view adapters and side-view adapters, a plurality of adapters with different outside diameters are present in accordance with the diameters of the distal end portions. Consequently, a plurality of kinds of adapters are individually attachable to and detachable from the distal end portion.
Further, a configuration is also well known, in which identification resistors differing in resistance value according to adapters are provided in a plurality of adapters attachable to and detachable from the distal end portion, and when an adapter is attached to the distal end portion, the identification resistor contacts a terminal for resistor identification provided in the distal end portion, whereby a control section which is electrically connected to the terminal reads the resistance value, and automatically detects the kind of the adapter attached to the distal end portion, from the resistance value.
However, when the identification resistor is provided in a limited space in an adapter, and the terminal for resistor identification is provided in a limited space in the distal end portion, there arises the problem that the adapter and the distal end portion increase in diameter.
In the light of the problem as above, Japanese Patent Application Laid-Open Publication No. 2004-33487 discloses the configuration of an endoscope system in which in the configuration where a plurality of known adapters for stereo measurement are individually attachable to and detachable from the distal end portion, two objective optical systems, and field of view masks that are located at rear sides in the respective optical axis directions of the respective objective optical systems and function as diaphragms in which openings that narrow down lights passing through the respective objective optical systems and differ in shape in accordance with the respective adapters are formed are provided in each of the respective adapters. Further, Japanese Patent Application Laid-Open Publication No. 2004-33487 discloses the configuration in which when the adapter is attached to the distal end portion, images of the lights which pass through the respective objective optical systems and the respective openings, and the field of view mask are respectively formed on the light receiving section of the image pickup device provided in the distal end portion, and two optical images and the opening shape of the field of view mask are displayed on the display section. Furthermore, Japanese Patent Application Laid-Open Publication NO. 2004-33487 discloses the configuration in which the CPU detects the opening shape of the field of view mask by image processing, and detects the kind of adapter which is attached to the distal end portion.